DESCRIPTION: (Applicant's Description) Core B, Pathology, will provide histological, immunohistochemical and immunofluorescence analyses of animal and human specimens for each project. (1) Histological and immunological analyses for neuroblastoma invasion and metastasis using animal models (Project 1). (2) Histological analyses of the effects by anti-angiogenesis agents on neuroblastoma by using animal models (Project 2). (3) Electron microscopic analysis of neutrophil-neuroblastoma cell interaction in ADCC. Histological and immunohistochemical analyses of immunocytokine and neutrophil localization into primary and metastatic neuroblastomas by using animal models (Project 3). (4) Histological analyses of tumors and normal organs of mice treated with retinoids and modifiers (Project 4). (5) Immunohistochemical analyses for expression of the factors related to angiogenesis (vascular endothelial cell integrins, denatured collagen type IV, proteases and their inhibitors) by human neuroblastoma tumors (Project 2). (6) Histological analyses of neuroblastomas to confirm diagnosis and risk classification, as required by clinical study (Project 5).